Wednesday, November 16, 2011

Reaction: Tree-Maps: A space filling approach to visualization of hierarchical information structures

The paper starts out with a motivation to visualize directory structures in a very neat and user friendly way. The first few paragraphs discuss why the existing methods like listings, outlines and trees dont really provide a good  visualization. The authors have pointed out that listings have details but lack the hierarchical structure of the directories. Trees on the other hand are very simple so they have just name labels as nodes and this doesnt really describe the document. They describe a new approach to visualization called treemaps. 

As an intermediate step they also describe using venn diagrams to depict the hierarchies. Venn diagrams are usually used for set visualizations. The authors claim that this is a odd use for venn diagrams. However i dont see think it is. Venn diagrams have been used to depict hierarchies in some other fields too like data mining. In data mining they are used to show the different clusters formed in hierarchical clustering. 

The treemap and its evolution is described very well. It is a nice visualization to the a good view of the entire directory structure. The treemap is based on venn diagrams it is built based on similar properties however it fits into a proper rectangle. Unlike the above mentioned methods of listings, trees etc it depicts the size of the objects and also the hierarchy of the directory structure in a single visualization. This representation has the potential to show other information like small groups across hierarchies using color. It also enables comparison of objects and so on. However one can argue that this approach too like the above mentioned approaches is not scalable and hence doesnt solve the major problem with visualizing bulk of hierarchically arranged data.